Method of fabricating thin film magnetic head including durable wear layer and non-magnetic gap structure

ABSTRACT

A thin film magnetic head is fabricated on a substrate by depositing a seed layer on the substrate. A lower magnetic layer is plated on the substrate in an opening provided in an insulative layer which is deposited on the seed layer. A plurality of magnetic layers are plated at one end of the lower magnetic layer to build-up and form a first side pole by using the above seed layer as a seed. Another plurality of magnetic layers are plated at the other end of the lower magnetic layer to build-up and form a second side pole by using the same seed layer as a seed. The first and second side poles thus formed include upper and lower ends, the lower ends being plated to the ends of the lower magnetic layer. A first upper pole is plated to the upper end of the first side pole. The first upper pole includes a gap end facing the second side pole. A gap region of nonmagnetic material is deposited adjacent the gap end of the first upper pole. A second upper pole is plated to the upper end of the second side pole and includes a gap end adjacent the gap region. A diamond-like carbon (DLC) frame is fabricated at the uppermost portion of the head surrounding the upper side poles and gap region. The DLC frame provides both structural integrity to the head and wear protection when the head contacts the media surface.

This Application is a Division of Ser. No. 08/650,587 filed May 20, 1996now U.S. Pat. No. 5,801,909.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This patent application is related to the copending patent applicationentitled "METHOD OF FABRICATING A THIN FILM MAGNETIC HEAD INCLUDINGLAYERED MAGNETIC SIDE POLES", (Attorney Docket No. M-2773U.S.) byMalhotra et al., filed concurrently herewith and assigned to the sameassignee, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates in general to magnetic recording and playbackheads and, more particularly, to thin film magnetic recording andplayback heads.

2. Description of Related Art

In the continuing drive for increased storage density in magnetic mediastorage devices, thin film magnetic heads have been developed. Asopposed to earlier types of magnetic heads, the fabrication of whichinvolves significant piecework and manual handling of individual parts,thin film magnetic heads take advantage of semiconductor fabricationprocesses to form a large number of heads simultaneously on a commonsubstrate or wafer.

One such head which is formed by a semiconductor thin film process isdisclosed in the article, "A New Thin Film Head Generation IC Head" byJ. P. Lazzari et al., IEEE Transactions on Magnetics, Vol. 25, No. 5,September 1989. A cross-sectional view of the Lazzari head isillustrated in FIG. 1 as head 10. Head 10 is fabricated within a recess15 in a silicon substrate 20. A gap 25 is shown in the uppermost portionof a magnetic layer or yoke 30 situated within recess 15. Head 10 isshown positioned adjacent magnetic recording media 35. A magnetic coil40 is wound around magnetic yoke 30. A plurality of sliders withrespective heads 10 thereon are fabricated from a common silicon waferor substrate using semiconductor thin film processes. The sliders arethen diced up into individual slider assemblies

Unfortunately, thin film magnetic heads are subject to substantial wearwhen the head contacts magnetic recording media such as tape, forexample. Over time, this wear can be very considerable and ultimatelymay be a cause for head failure if accumulated wear significantlydamages the head.

SUMMARY OF THE INVENTION

One advantage of the thin film head of the present invention issignificantly reduced head wear.

Another advantage of the thin film head of the present invention is anarrow gap width which results in correspondingly high density magneticrecording capabilities.

Still another advantage of the thin film head of the present inventionis that the disclosed head can be fabricated in large quantities usingthin film semiconductor fabrication equipment.

In accordance with one embodiment of the present invention, a thin filmmagnetic head is provided which includes a substrate and a lower polemember of magnetic material situated on the substrate and having firstand second ends. The head includes first and second side pole members ofmagnetic material situated at the first and second ends, respectively,of the lower pole member. The first and second side pole members arebuilt up from a plurality of layers of magnetic material deposited layerupon layer. The first and second side pole members include tops andbottoms. The head also includes a conductor coil situated around one ofthe first and second side pole members and separated from the first andsecond side pole members by insulative layers. The head further includesan insulative pedestal situated at the tops of the first and second sidepole members, the insulative pedestal extending above the plane of theinsulative layers below and surrounding the tops of the first and secondside pole members. The head includes first and second magnetic polessituated atop the pedestal, the first magnetic pole extending from thefirst side pole toward the second side pole, the second magnetic poleextending from the second side pole toward the first magnetic pole. Agap region is formed between the first and second magnetic poles and isfilled with nonmagnetic material. The head further includes adiamond-like carbon (DLC) frame situated atop the pedestal andsurrounding the first and second magnetic poles. The DLC frame providesboth structural integrity to the head and wear protection therefor.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel are specifically setforth in the appended claims. However, the invention itself, both as toits structure and method of operation, may best be understood byreferring to the following description and accompanying drawings.

FIG. 1 is a cross section of a conventional thin film magnetic head.

FIG. 2A is a plan view of a substrate with via holes employed by oneembodiment of the magnetic head of the invention.

FIG. 2B is a cross section of the magnetic head of FIG. 2A taken alongsection line 2B--2B.

FIG. 3 is a plan view of the magnetic head of FIG. 2A with a seed layeradded.

FIG. 4A is a plan view of the magnetic head of FIG. 3 with an insulativelayer and open region formed therein.

FIG. 4B is a cross sectional view of the magnetic head of FIG. 4A takenalong section line 4B--4B.

FIG. 5 illustrates a plurality of magnetic heads being fabricated on acommon substrate.

FIG. 6A is a plan view of the magnetic head of FIG. 4A showing an earlystage of side pole build-up

FIG. 6B is a cross sectional view of the magnetic head of FIG. 6A takenalong section line 6B--6B.

FIG. 7A is a plan view of the magnetic head of FIG. 6A showing theplacement of a lower coil structure.

FIG. 7B is a cross sectional view of the magnetic head of FIG. 7A takenalong section line 7B--7B.

FIG. 8A is a plan view of the magnetic head of FIG. 7A showing aninsulative layer on the lower coil structure.

FIG. 8B is a cross sectional view of the magnetic head of FIG. 8A takenalong section line 8B--8B.

FIG. 9A is a plan view of the magnetic head of FIG. 8A showing placementof an upper coil structure.

FIG. 9B is a cross sectional view of the magnetic head of FIG. 8A takenalong section line 9B--9B.

FIG. 10A is a plan view of the magnetic head of FIG. 9A showing aninsulative layer on the upper coil structure.

FIG. 10B is a cross sectional view of the magnetic head of FIG. 10Ataken along section line 10B--10B.

FIG. 11A is a plan view of the magnetic head of FIG. 10A showingplacement of a seed layer and a connective grounding strip.

FIG. 11B is a cross sectional view of the magnetic head of FIG. 11Ataken along section line 11B--11B.

FIG. 12 is a cross sectional view of the magnetic head of FIG. 11Bshowing placement of an insulative pedestal thereon.

FIG. 13A is a cross sectional view of the magnetic head of FIG. 13Bshowing the further build-up of the magnetic side poles.

FIG. 13B is a close-up plan view of a portion of the head of FIG. 13Ashowing the side pole and insulative pedestal area.

FIG. 14A is a cross sectional view of the magnetic head of FIG. 14Bshowing the addition of a first magnetic pole at the top of the magneticyoke structure of the head.

FIG. 14B is a close-up plan view of a portion of the head of FIG. 14Ashowing the first magnetic pole.

FIG. 14C is a cross-sectional view of the head showing a photoresistlayer with an open region in which gap material is to be deposited.

FIG. 15A is a close-up plan view of a portion of the head of FIG. 14Ashowing the gap region of the head.

FIG. 15B is a cross sectional view of the magnetic head of FIG. 15Ashowing the addition of a gap region.

FIG. 16A is a close-up plan view of the side pole and gap region of themagnetic head of FIG. 15A showing the addition of a second magnetic poleat the top of the magnetic yoke structure of the head.

FIG. 16B is a cross sectional view of the magnetic head of FIG. 16Ataken along section line 16B--16B and showing the addition of a secondmagnetic pole.

FIG. 17A is a close-up plan view of the side pole and gap region of themagnetic head of FIG. 16A after addition of an adhesion layer and adiamond-like carbon wear layer to the top of the head.

FIG. 17B is a cross sectional view of the magnetic head of FIG. 17Ataken along section line 17B--17B.

FIG. 18A is a cross sectional view of the magnetic head of FIG. 17Bshowing the magnetic head after a diamond-like carbon wear layer andadhesion layer are patterned and etched in regions other than theinsulative pedestal.

FIG. 18B is a close-up view of the upper portion of the head of FIG.18A.

FIG. 19A is a close-up view of the side pole and gap region of themagnetic head when fabrication is complete.

FIG. 19B is a cross section view of the magnetic head of FIG. 19A takenalong section line 19B--19B.

FIG. 19C is a close-up view of the uppermost portion of the head of FIG.19B

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2A shows a portion of a thin film head 100 which is situated on aninsulative substrate 105 such as a ceramic, alumina or othernonconductive substrate. Substrate 105 includes opposed surfaces 105Aand 105B. Via holes 110 are formed in substrate 105 and are filled withan electrically conductive material to create conductive paths throughsubstrate 105 at the locations shown. Laser drilling or other highprecision via formation technique may be employed to form via holes 110.Via holes 110 are filled with electrically conductive material such asplated copper, thick film processed gold, or sintered tungsten andcopper, for example, to form via connective members 112A, 112B and 112C.Connective members 112A and 112C will subsequently be coupled to theends of a coil structure and connective member 112B will be coupled toground. In one embodiment of the invention wherein the magnetic head isungrounded, via hole 112B is omitted. In actual practice, substrate 105is a wafer on which the FIG. 2A pattern is replicated thousands oftimes.

A seed layer 115 of an electrically conductive material suitable forplating is sputtered on substrate surface 105A. For example, seed layer115 may be fabricated from Cr--NiV, namely, a chrome or otheradhesion-promoting layer followed by a non-magnetic nickel-vanadium 7%film. Via caps 120 are patterned using photolithographic techniques andplated on seed layer 115 at the tops of vias 110 as shown in FIGS. 2Aand 2B. More specifically, to pattern via caps 120, a photoresist layer(not shown) is deposited on seed layer 115 and patterned to includeopenings above connective members 112A, 112B and 112C at which theformation of respective via caps 120 is desired. Plating is thenconducted in these openings using seed layer 115 as the seed. Thephotoresist is then removed, thus leaving patterned via caps 120. Asused in this document, the term "patterning" will mean the formation ofa particular layer such that the layer exhibits a specified pattern,such as described with respect to the formation of via caps 120 above,for example.

Via caps 120 are fabricated from NiFe by any suitable deposition orplating process. It is noted that later in the process described herein,portions of seed layer 115 will be removed by sputter etching. While inthe particular example described, via caps 120 are fabricated from NiFe,in actual practice via caps 120 can be fabricated from other conductivematerials which would not be attacked by the particular etchant used tolater remove Cr--Cu seed layers 185, 230 and 275. Via caps 120 areregarded as being a part of via connective members 112A, 112B and 112C.

Seed layer 115 is also used to pattern and NiFe plate photolithographicalignment targets (not shown) for registration of subsequent layers. Theexposed portions of seed layer 115 are then sputter etched away leavingvia caps 120 and the alignment targets intact. It should be appreciatedthat seed layer 115 served as a sacrificial layer for the purpose ofenabling plating of via caps 120.

In the next step of the process, a Cr--NiV seed layer 130 is formed onthe structure of FIG. 2B after seed layer 115 is etched away. Seed layer130 is formed in the shape of a ground structure 125 which extendsaround the periphery of head 100 on substrate 105 and laterally acrossthe middle of head 100 as shown in FIG. 3. Open regions 117A and 117Bare thus formed in seed layer 130 which respectively isolate viaconnective members 112A and 112C from ground structure 125 and viaconnective member 112B. In the embodiment depicted in FIG. 3, viaconnective member 112B is coupled to ground structure 125. To actuallyform seed layer 130, a "lift-off" process is used. In this "lift-off"process, photoresist (not shown) is patterned covering open regions 117Aand 117B (see FIG. 3). Seed layer 130 is then sputtered on the entireupper surface of the partially completed head 100. The photo-resistwhich covers open regions 117A and 117B is now "lifted-off" head 100. Toaccomplish this lift-off, the partially complete head 100 is placed inan ultrasonic bath including a photoresist solvent such as acetone, forexample. The seed layer 130 is sufficiently thin such that it does notcover photoresist layer at open regions 117A and 117B very well. In thismanner, there are sufficient avenues of attack by which the solvent canget through seed layer 130 at the edges of open regions 117A and 117B todissolve the photoresist layer at open regions 117A and 117B. When thephotoresist layer at open regions 117A and 117B is thus dissolved, theportions of seed layer 130 immediately above open regions 117A and 117Blift-off and float away. The region of head 100 at open regions 117A and117B is thus void of seed layer 130 as shown in FIG. 4C.

An insulative layer 135 of photoresist is patterned on head 100 as shownin FIG. 4B. Insulative layer 135 is cured with an electron beam.Exposing the photoresist to an E-beam for a time within the range ofapproximately 20 minutes to approximately 40 minutes is found to produceacceptable curing results. Insulative layer 135 includes an open region140 for receiving the lowermost portion of a magnetic yoke 145 therein.More particularly, a layer 150 of magnetic material such as NiFe ispatterned and plated on seed layer 130 within open region 140 to formthe lowermost portion of magnetic yoke 145. Magnetic layer 150 exhibitsa thickness of approximately 5 microns to approximately 6 microns inthis particular embodiment. When reference is made to "magnetic layers"or other magnetic structures in this document, it should be understoodthat layers of magnetically permeable material are being referenced.Magnetic layer 150 forms the bottom pole of magnetic yoke 145. Seedlayer 130, or more specifically the middle section of the groundstructure 125 thereof, acts as a base upon which magnetic yoke 145 isbuilt up layer by layer. Magnetic layer 150 is plated up to a level suchthat it is level with insulative layer 135.

For convenience, one half of head 100 is depicted in FIG. 4A andsubsequent figures. It should be understood that substantially the samestructure as shown in FIG. 4A and the subsequent figures is repeated toform the actual head. More particularly, in the particular embodimentshown, head 100 is symmetric about major axis 155 such that head 100actually includes two recording or playback portions. In actualpractice, a plurality of heads 100 are fabricated simultaneously on acommon semiconductor substrate 105 as shown in FIG. 5. For example, 5000or more heads may be fabricated at the same time on the same substrate.FIG. 5 shows another embodiment of head 100, namely an ungroundedversion in which via connective member 112B is omitted.

An insulative layer 160 of photoresist is patterned on head 100 as shownin FIG. 6A and 6B. Insulative layer 160 is electron beam cured toprovide a planar surface as illustrated. The thickness of insulativelayer 160 in this particular embodiment is approximately 2 microns.Insulative layer 160 includes open regions 165 and 170 in whichrespective magnetic side poles are built up. More specifically, amagnetic side pole portion 175 is plated in open region 165 up to aheight which is level with insulative layer 160, and a magnetic sidepole portion 180 is plated in open region 170 up to a height which islevel with insulative layer 160.

A seed layer 185 is sputtered on insulative layer 160 of the partiallyformed head 100 of FIG. 6A to form a plating base for a lower coil layer190 as shown in FIG. 7A. Seed layer 185 is drawn sufficiently thin suchthat it does not appear to have significant vertical dimension in FIG.7A. Seed layer 185 is fabricated from CrCu in one embodiment.

A lower coil layer 190 is formed on seed layer 185 as shown. One way toform lower coil member 190 is to deposit a layer of photoresist (notshown) on seed layer 185. This photoresist layer is then patterned usingconventional photolithographic techniques which includes photoresistapplication, masking, exposure, developing, and so forth. Morespecifically, the photoresist layer is patterned to cover the entiresurface of seed layer 185 except for openings at the locations where thecoil elements of lower coil layer 190 are to be formed. Head 100 is thensubjected to a plating bath of copper. copper is thus plated in theopenings of the photoresist layer to form lower coil layer 190. Thethickness of coil layer 190 is within the range of approximately 3 μ toapproximately 3.5 μ at this stage.

Lower coil layer 190 includes a connective strip 195 made ofelectrically conductive material which couples an end 190A of coil layer190 to the via cap 120 of via connective member 112A. Copper plating maybe used to fabricate connective strip 195 as part of the above step offorming loser coil layer 190. The remaining end 190B of lower coil layer190 is located at the center of the lower coil. Head 100 is then etchedto remove seed layer 185 from those portions of head 100 not protectedby lower coil layer 190.

An insulative layer 200 of photoresist is patterned on head 100 abovelower coil layer 190 leaving an open region 205 for access to coil end190B as shown in FIGS. 8A and 8B. The thickness of insulative layer 200is within the range of approximately 5 μ to approximately 6 μ.Insulative layer 200 is also patterned to leave open regions 210 and 215above side pole portion 175 and side pole portion 180, respectively.Insulative layer 200 is electron beam cured. Insulative layer 200electrically isolates lower coil layer 190 from structures subsequentlyplaced above layer 190.

Magnetic side pole portions 220 and 225 are plated on side pole portions175 and 180, respectively, as shown in FIGS. 8A and 8B. Side poleportions 220 and 225 are plated with a magnetic material such as NiFe upto a level even with that of insulative layer 200.

A seed layer 230 is sputtered on insulative layer 200 of the partiallyformed head 100 of FIG. 8B to form a plating base for an upper coillayer 235. Seed layer 230 is drawn sufficiently thin such that it doesnot appear to have significant vertical dimension in FIG. 8B. Seed layer230 is fabricated from CrCu in one embodiment. Upper coil layer 235 ispatterned and copper plated on seed layer 230 as shown in FIG. 9A and9B. FIG. 9B is a simplified cross-section of head 100 at the describedstage of fabrication in which structures in back of upper coil layer 235are not shown in order to emphasize upper coil layer 235. In thisparticular embodiment, upper coil layer 235 is substantially similar ingeometry to lower coil layer 190 and is fabricated using substantiallythe same technique. However, other coil arrangements are possible ifdesired. Head 100 is then etched to remove seed layer 230 from thoseportions of head 100 not protected by upper coil layer 235.

Upper coil layer 235 includes a connective strip 237 made ofelectrically conductive material which couples an end 235A of upper coillayer 235 to the via cap 120 of via connective member 112C. Copper maybe used to fabricate connective strip 237. The remaining end 235B ofupper coil layer 235 is coupled to lower coil end 190B through openregion 205, shown later in FIG. 10B, by a plated connectiontherebetween.

An insulative layer 240 of photoresist material is deposited andpatterned on head 100 as shown in FIGS. 10A and 10B. Insulative layer240 electrically isolates upper coil layer 235 from the other structuresof head 100. Insulative layer 240 includes open regions 245 and 250 intowhich magnetic side pole portions 255 and 260 are respectively plated.More specifically, magnetic side pole portions 255 and 260 are plated upto a level even with insulative layer 240 as shown in FIG. 10B.

Magnetic side pole portions 175, 220 and 255 together form a first sidepole 265. Magnetic side pole portions 180, 225 and 260 together form asecond side pole 270. First side pole 265, second side pole 270 andbottom pole 150 together form a significant portion of magnetic yoke145.

A seed layer 275 fabricated of CrCu material is formed on the uppersurface of the head structure 100 as shown in FIG. 11B. Seed layer 275is sputtered, patterned and chemically etched on the upper surface ofhead 100 to include an open region 280 above the side pole structurealso as shown in FIG. 11B. Seed layer 275 is formed by an adhesion layerof chromium (Cr) on the upper surface of head 100 followed by a layer ofcopper (Cu). The chromium adhesion layer enhances the adherence of thecopper portion of seed layer 275 to upper surface of head 100.

The primary requirement in selection of the material for seed layer 275is that seed layer 275 be chemically etchable without damage to theexposed NiFe. Copper is an example of a material that meets thisrequirement and is also used for the coil seed layers. Chrome is used asthe adhesion layer for copper. It is noted that a titanium-tungsten seedlayer (Ti 10%; W 90%) which wet etches easily can also be used for seedlayer 275.

Protective caps 285 and 290 are patterned over connective strips 195 and237, respectively. Caps 285 and 290 are fabricated from NiFe by platingin one embodiment. A material such as nickel, nickel-phosphorus 7-10%,or gold may be used to provide environmental protection for theunderlying plated copper connective strips.

In an embodiment of head 100 wherein head 100 is grounded, a groundingconnective strip 295 is also patterned and plated in the same processstep as protective caps 285 and 290. Grounding strip 295 connects groundvia connective member 112B and magnetic yoke 145 through seed layer 130.Grounding strip 295 is fabricated from the same material as protectivecaps 285 and 290 in this particular embodiment.

An electrically insulative layer of photoresist is patterned andelectron beam cured to form a protrusion or pedestal 300 on the upperportion of head 100 as shown in FIG. 12. Insulative pedestal 300exhibits a substantially rectangular geometry with rounded corners inthis particular embodiment, although other geometries may be used ifdesired. Insulative pedestal 300 includes open regions 305 and 310 forside poles 265 and 270 of the magnetic yoke. Open regions 305 and 310are filled with magnetic material by plating side poles 265 and 270 withNiFe up to the level of the top of insulative layer 300 as shown in FIG.13A. Magnetic side pole portions 315 and 320 are thus formed in openregions 305 and 310. Magnetic side pole portions 315 and 320 form theuppermost parts of first side pole 265 and second side pole 270,respectively.

A frame 325 of magnetic material, for example NiFe, is patterned aroundinsulative pedestal 300 at the same time that magnetic side poleportions 315 and 320 are plated. Plating or other suitable depositiontechnique is used to form frame 325. Frame 325 exhibits a thickness ofapproximately 5 μ in this particular embodiment. Seed layer 275 acts asthe seed for the plating of frame 325. Frame 325 exhibits asubstantially rectangular shape in this particular embodiment andsurrounds insulative pedestal 300 which forms the inner boundary offrame 325 as seen in FIG. 13B. Shapes other than rectangular can be usedfor frame 235 as long as frame 325 substantially surrounds, and islocated immediately adjacent to, pedestal 300. Frame 325 serves tostiffen insulative pedestal 300 and may provide electrical shielding ofthe contained structures. FIG. 13B is a close-up view of the coil andside pole regions of head 100 at the present stage in the fabrication ofhead 100. Alternatively, side pole portions 315 and 320 are fabricatedas before, but frame 325 is subsequently patterned and plated withnon-magnetic NiP alloy up to a level even with the top of insulativepedestal 300. The innermost boundary of seed layer 275 which abuts itsopen region 280 is shown in dashed line in FIG. 13B. The exposed CrCuseed layer 275 is removed by wet chemical etching.

Referring now to FIGS. 3, 14A and 14B, a layer of photoresist ispatterned covering open regions 117A and 117B (see FIG. 3) and furthercovering side poles 265 and 270 (see FIGS. 14A and 14B). A Cr--NiV seedlayer 330 is sputtered on the exposed upper surfaces of head 100. Thephoto-resist is stripped as in the earlier-described "lift-off" process,thus "lifting off" the sputtered Cr--NiV film from regions 117A and117B. During this photoresist stripping step, the photoresist above sidepoles 265 and 270 is removed to form open regions 335 and 340 as shownin FIG. 14A. Side poles 265 and 270 are thus exposed.

A first magnetic pole 345 is patterned at the top of magnetic yoke 145as shown in FIGS. 14A and 14B. First magnetic pole 345 is fabricated byplating a magnetic material such as NiFe on side pole 265 and on aportion of seed layer 330 adjacent side pole 265. Magnetic controlregions 350 and 355, which are adjacent both sides of first magneticpole 345, may be patterned and plated at the same time as first pole345. Magnetic control regions 350 and 355 serve to better control localplating current density which influences NiFe composition and enhancesthe effect of the easy axis magnetic orienting field of betweenapproximately 1000 Gauss to approximately 10,000 Gauss, provided by anexternal magnet during the first magnetic pole plating step, to give adesired magnetic domain structure in the magnetic pole piece. Head 100is exposed to the same magnetic field throughout the duration ofbuilding up the various magnetic layers thereof.

A substantially rectangular gap region 360 of non-magnetic material ispatterned adjacent pole end 345A as shown in FIG. 15A and the head crosssection of FIG. 15B. One non-magnetic material which may be used toplate gap region 360 on head 100 is NiP. Other non-magnetic materialswhich are acceptable for plating as gap region 360 are chrome andrhodium, for example. While in this particular embodiment, plating isused to lay down gap region 360, other suitable deposition techniquessuch as chemical vapor deposition (CVD), patterning and etching unwantedCVD film, may also be employed.

In actual practice, to pattern non-magnetic gap region 360 on head 100,the upper surface of head 100 is coated with photoresist except for theportion shown as gap region 360 in FIG. 15B. More particularly, FIG. 14Cillustrates the formation of such a photoresist layer as photoresistlayer 362 with an open region 364 in which non-magnetic gap region 360is to be plated. Non-magnetic material such as NiP is then plated aboveseed layer 330 and in open region 364 to form gap region 360. In thisparticular embodiment, gap region 360 is approximately mid way betweenside poles 265 and 270. Other embodiments are possible wherein gapregion 360 is offset either toward side pole 265 or side pole 270.

A second magnetic pole 365 is patterned and plated at side pole 270 atthe top of magnetic yoke 145 as shown in FIGS. 16A and 16B. Secondmagnetic pole 365 includes a pole end 365A which is situated adjacentpole end 345A and which is separated from pole end 345A by gap region360. It is noted that pole 345 becomes narrower from side pole 265 topole end 345A. Similarly, pole 365 becomes narrower from side pole 270to pole end 365A. This gives poles 345 and 365 a bow tie-like appearancein this particular embodiment. Other pole geometries may be used aswell. Pole ends 345A and 365A are alternatively referred to as gap ends.First magnetic pole 345 and second magnetic pole 365 exhibit a thicknessof approximately 5 μ.

Magnetic control regions 370 and 375 are patterned and plated adjacentboth sides of second pole 365 to enhance magnetic control as shown inFIG. 16A. Control regions 350, 355, 370 and 375 are fabricated from amagnetic material such as the material used to fabricate second magneticpole 365. For optimal wear performance, the area of NiFe exposed to therecording media should be minimized. Thus, to avoid possible magneticeffects that may degrade recording performance, NiFe plated magneticcontrol regions 350, 355, 370 and 375 are patterned with photoresist andetched away leaving a pole geometry seen in FIG. 17A.

Magnetic side pole portions 175, 220, 255 and 315 together make up afirst side pole which is shown collectively as side pole 265 in FIG.16B. Magnetic side pole portions 180, 225, 260 and 320 together make upa second magnetic side pole which is shown collectively as side pole 270in FIG. 16B. Magnetic yoke 145 is collectively made up of bottommagnetic layer 150, side poles 265 and 270, and magnetic poles 345 and365.

The exposed seed layer 330 is removed by sputter etching. Alternatively,seed layer 330 is not etched, but is permitted to remain. A siliconadhesion layer 380 is sputtered on the exposed upper surface of head 100as shown in FIG. 17B. A diamond-like carbon (DLC) protective wear layer385 is then deposited on adhesion layer 380. Adhesion layer 380 enablesDLC layer 385 to stick to the upper surface of head 100. This siliconadhesion layer typically exhibits a thickness within the range ofapproximately 400 A° to approximately 1000 A°. This silicon adhesionlayer exhibits a nominal thickness of approximately 600 A° in apreferred embodiment.

DLC layer 385 covers at least the top of magnetic yoke 145 and theimmediately surrounding area of the head. As seen in FIG. 17A and moreclearly in FIG. 17B, a hard protective wear layer 385 covers magneticyoke 145 and insulative pedestal 300. Protective layer 385 exhibits aKnoop hardness greater than 700 Knoop and preferably greater than 800Knoop. The hardness of protective layer should be within the range ofgreater than approximately 700 Knoop to approximately 2000 Knoop. Onematerial that is satisfactory for formation of protective wear layer 385is diamond like carbon (DLC).

To form such a DLC wear layer 385, DLC layer 385 is chemically vapordeposited and patterned. More specifically, both DLC layer 385 andadhesion layer 380 are reactive ion etched to leave a DLC wear layer385' over magnetic yoke 145 and insulative pedestal 300 as shown in FIG.18A. Prior to exposing head 100 to this reactive ion etch, the uppersurface of head 100 is covered with a layer of photoresist (not shown).The photoresist layer is patterned to include unprotected open regionsfor those portions of the head external to frame 325. In this manner,when the head is subjected to the reactive ion etch, the portion of DLClayer 385 external to frame 325 is etched away and the remaining portionof DLC layer 385 is protected and remains as DLC layer 385'.

An alternative to the above described photoresist masking approach topatterning DLC layer 385 into DLC layer 385' is to cover head 100 with ametal layer such as chromium. For example, a relatively thin photomasklayer (not shown) of chromium is sputtered over the DLC layer. In thisparticular example, the photomask layer is approximately 500 A° thick.The metal photomask layer is photo-patterned and etched to expose DLCareas which are to be excavated by reactive ion etching. The DLC layeris then reactive ion etched to the desired DLC structure.

More detail is now provided with respect to the formation of DLCprotective wear layer 385. Before DLC protective wear layer 385 isactually laid down on silicon adhesion layer 380, adhesion layer 380 issputter cleaned. In the course of performing this sputter cleaning,approximately 200 A° of the upper surface of silicon adhesion layer 380is removed. More particularly, the silicon adhesion layer is sputtercleaned in a SAMCO plasma machine, Model No. PD-200D (Plasma EnhancedCVD System For DLC Deposition and Etching), hereafter the "plasmamachine". This sputter cleaning is performed with Argon in a plasmawithin the plasma machine vessel at a pressure of 70 mTorr with 180watts RF input power at a frequency of 13.56 MHz. The flow rate of Argonis approximately 100 sccm. The partially complete head 100 is situatedon a 6 inch diameter cathode (ie. the energized electrode) of the SAMCOplasma machine, Model PD-200D, for approximately 3 to approximately 4minutes.

Immediately after the Argon plasma cleaning (sputter etching) iscomplete, the input power is reduced to 110-150 Watts to the same 6 inchcathode electrode. The Argon source is turned off and a source of liquidhydrocarbon DLC source material is turned on. For example, one DLCsource material that may be used is Part No. S-12 available from SAMCO,Sunnyvale, Calif. The pressure within the vessel is approximately20-approximately 25 mTorr at a flow rate of source material ofapproximately 25 cm³ /min. Although the temperature is not specificallycontrolled during this process, the wafer on which the head isfabricated is situated on a water-cooled cathode while in the plasmamachine. Under these conditions, a DLC deposition rate of approximately1000 A/min is obtained which is maintained until the desired DLCthickness is reached, namely approximately 5 μ.

DLC fabricated in this manner results in a DLC layer 385 with a Knoophardness of approximately 800. It is found that DLC layer Knoophardnesses of greater than 700 up to approximately 2000 Knoop produceand acceptably hard wear layer 385 for wear protection purposes. DLCwear layer 385 is then reactive ion etched as described to form DLC wearlayer 385'.

FIG. 18B is a close-up view of the upper portion of head 100 at thestage of fabrication depicted in FIG. 18A. In this close-up view, it canbe seen that gap region 360 includes a main gap portion 360B which issubstantially normal to seed layer 330 and the substrate therebelow. Gapregion 360 also includes a top 360A which extends from the uppermostpart of main gap portion 360B and generally parallel to seed layer 330and magnetic pole 345. Top 360A overlies a portion of magnetic pole 345and extends from main gap portion 360B toward side pole 265. Gap region360 further includes a bottom portion 360C which extends from thelowermost part of main gap portion 360B and generally parallel to seedlayer 330 and magnetic pole 365. Bottom portion 360 underlies a portionof magnetic pole 365 and extends from main gap portion 360B toward sidepole 270.

DLC wear layer 385' is machined as shown in FIG. 19B to expose and shapemagnetic gap region 360' as shown in both FIG. 19A and 19B. A machinedwear layer 385" thus results. The gap region 360' exposed and shaped bythis machining step exhibits a substantially L-shaped cross section asseen in FIG. 19B and more clearly in the close-up view of FIG. 19C. DLCwear layer 385" protects head 100, specifically gap region 360 andmagnetic poles 345, 365, from wear when head 100 is brought into contactwith a magnetic media for recording or playback purposes. Wear layer385" which is relatively hard compared with the relatively soft gapregion 360' and magnetic poles 345 and 365, acts as protective bumperwhen head 100 comes into contact with the magnetic media. It is notedthat in this particular embodiment, the upper surface of wear layer 385is substantially flush with the upper surface of magnetic poles 345, 365and gap region 360'. Wear layer 385' surrounds magnetic poles 345, 365and gap region 385'. Wear layer 385' provides structural support for themagnetic poles 345, 365 and gap region 360' contained within its bounds.In this manner, wear layer 385' contributes to the structural integrityof head 100 and enhances the wear capabilities of the head.

By using the techniques described herein, very narrow gap regions can beproduced. The gap width, W_(G), is defined to be the width of gap region360, namely the distance between pole end 345A and pole end 365A as seenin FIGS. 19B and 19C. Typical gap widths for head 100 are approximately0.2 microns to approximately 1 micron.

It is noted that in one embodiment of the invention, the upper magneticpole elements 345 and 365 are plated directly on magnetic side poles 265and 270, respectively, Advantageously, no intervening structures arerequired between upper magnetic pole element 345 and magnetic side pole265 or between magnetic pole element 365 and magnetic side pole 270.

While a thin film magnetic head apparatus has been described above, itis clear that a method of fabricating such a magnetic head apparatus isalso disclosed. Briefly, a method of fabricating a thin film magnetichead is provided which includes the step of depositing a first seedlayer on a substrate. The method also includes the step of plating alower magnetic layer on the first seed layer, the lower magnetic layerhaving first and second opposed ends, the first seed layer being theseed for plating the lower magnetic layer. The method further includesthe step of plating a plurality of layers of magnetic material at thefirst end of the lower magnetic layer to build-up a first side polehaving a first top end, this plating step using the first seed layer asa common seed for the build-up of the plurality of layers of the firstside pole. The method includes the step of plating a plurality of layersof magnetic material at the second end of the lower magnetic layer tobuild-up a second side pole having a second top end, this plating stepusing the first seed layer as a common seed for the build-up of theplurality of layers of the second side pole. The method also includesthe step of forming a coil structure about one of the first and secondside poles. The method further includes the step of forming aninsulative body about the first and second side poles and the coilstructure. The method still further includes the step of forming aninsulative pedestal above the insulative body, the first and second topends extending through the pedestal. The method includes the step ofdepositing a second seed layer including first and second portions onthe insulative pedestal except for the first and second top endsextending through the pedestal. The method also includes the step ofdepositing a first upper magnetic pole element at the first top end andon the first portion of the second seed layer, the first upper magneticpole element including a first gap end extending toward the second topend. The method further includes the step of forming a gap region ofnonmagnetic material at the first gap end of the first upper magneticpole element. The method still further includes the step of depositing asecond upper magnetic pole element at the second top end and on thesecond portion of the second seed layer, the second upper magnetic poleelement including a second gap end situated adjacent the gap region. Themethod also includes the step of removing the second layer except forportions of said second seed layer below the first and second uppermagnetic pole elements and the gap region. The method further includesthe step of forming a diamond-like carbon (DLC) frame above theinsulative pedestal and surrounding the first and second upper magneticpole elements and gap region to provide structural integrity to the headand wear protection therefor.

The foregoing has described a thin film magnetic head in which the lowerelement of the magnetic yoke and two side poles are built up from acommon seed layer, namely seed layer 130. The disclosed head desirablyexhibits enhanced wear characteristics. Advantageously, the disclosedthin head achieves a very narrow gap width which results incorrespondingly high density magnetic recording capabilities. The thinfilm head can be fabricated without excavating a recess within thesubstrate to contain the head. Moreover, the disclosed thin film headcan be fabricated in large quantities using thin film semiconductorfabrication equipment.

While only certain preferred features of the invention have been shownby way of illustration, many modifications and changes will occur. Itis, therefore, to be understood that the present claims are intended tocover all such modifications and changes which fall within the truespirit of the invention.

What is claimed is:
 1. A method of fabricating a thin film magnetic headcomprising:depositing a first seed layer on a substrate having asubstantially planar surface; plating a lower magnetic layer on thefirst seed layer, the lower magnetic layer having first and secondopposed ends, the first seed layer being the seed for plating the lowermagnetic layer; plating a plurality of layers of magnetic material atthe first end of the lower magnetic layer to build-up a first side polestacked so that the plurality of layers form a first column in adirection perpendicular to the substrate surface and having a first topsurface, this plating step using the first seed layer as a common seedfor the build-up of the plurality of layers of the first side pole;plating a plurality of layers of magnetic material at the second end ofthe lower magnetic layer to build-up a second side pole stacked so thatthe plurality of layers form a second column in a directionperpendicular to the substrate surface and having a second top surface,this plating step using the first seed layer as a common seed for thebuild-up of the plurality of layers of the second side pole; forming acoil structure about one of the first and second side poles; forming aninsulative body about the first and second side poles and the coilstructure; forming an insulative pedestal in a generally horizontalplane overlying the insulative body and extending laterally to fullyenclose the first and second side pole top surfaces; forming a firstaperture in the insulative pedestal overlying the first side pole and asecond aperture in the insulative pedestal overlying the second sidepole; plating a layer of magnetic material overlying the first side poleextending through the first aperture in the insulative pedestal andplating a layer of magnetic material overlying the second side poleextending through the second aperture in the insulative pedestal;depositing a second seed layer including first and second portions onthe insulative pedestal leaving undeposited the layers of magneticmaterial of the first and second side poles extending through the firstand second apertures; depositing a first upper magnetic pole element atthe first top surface, integrally, directly and magnetically coupled tothe first side pole, and on the first portion of the second seed layer,the first upper magnetic pole element including a first gap endextending toward the second top surface; forming a gap region ofnonmagnetic material at the first gap end of the first upper magneticpole element; depositing a second upper magnetic pole element at thesecond top surface, integrally, directly and magnetically coupled to thesecond side pole, and on the second portion of the second seed layer,the second upper magnetic pole element including a second gap endsituated adjacent the gap region; removing the second seed layer exceptfor portions of said second seed layer below the first and second uppermagnetic pole elements and the gap region; and forming a diamond-likecarbon (DLC) frame above the insulative pedestal and surrounding thefirst and second upper magnetic pole elements and gap region to providestructural integrity to the head and wear protection therefor.
 2. Themethod of claim 1 further comprising depositing an adhesion layer on thehead prior to the step of forming a DLC frame.
 3. The method of claim 1wherein forming the DLC frame includes:depositing a DLC layer on thepedestal; and machining the DLC layer, the first and second magneticpole elements and the gap region to expose the first and second magneticpole elements and the gap region.
 4. The method of claim 3 whereindepositing a DLC layer on the pedestal includes:depositing a DLC coatingover the pedestal and insulative body; reactive ion etching the DLCcoating to remove the DLC coating except for the portion thereof abovethe insulative pedestal.
 5. The method of claim 1 furthercomprising:forming the gap region by plating the gap region.
 6. Themethod of claim 1 wherein the gap region exhibits a substantiallyL-shaped form in a cross-sectional plane perpendicular to thesubstantially planar surface of the substrate and extending through thefirst and second side poles.
 7. A method of fabricating a thin filmmagnetic head comprising:electroplating a magnetic material to form alower pole member on a substrate having a substantially planar surface,the lower pole member having first and second ends; forming a commonseed layer on the first and second ends of the lower pole member;electroplating a plurality of layers of the magnetic material, layerupon layer in a direction perpendicular to the substrate surface, toform first and second side pole members at the respective first andsecond ends of the lower pole member overlying the common seed layer,the individual layers of the plurality of layers of the magneticmaterial being the same size and shape and stacked directly connectingwith a preceding layer so that the plurality of layers form a column,both the first and second side pole members including a top surface anda bottom surface, the common seed layer being common to each layer ofthe plurality of layers of the magnetic material; depositing a pluralityof layers of an electrically insulative material to form an insulativebody about the first and second side poles, the layers of the insulativematerial being built up in the insulative body alternately with abuild-up of the layers of the magnetic material in the side polemembers; depositing a plurality of coil layers to form first and secondconductor coils having a plurality of coil segments that are mutuallyinsulated by the layers of electrically insulative material within theinsulative body, the first and second conductor coils being wound toencircle the first and second side pole members, respectively, theplurality of coil layers being built up alternately with the build-up oflayers of the insulative body and layers of the magnetic material in theside pole members; depositing an insulative pedestal disposed in a planesubstantially parallel to the planar surface of the substrate andgenerally overlying the first and second pole members and extendinglaterally so that top surfaces of the first and second side pole membersare completely enclosed within an exterior boundary of the insulativepedestal; etching a first aperture and a second aperture in theinsulative pedestal respectively overlying the first side pole memberand the second side pole member so that the top surfaces of the firstand second pole members are exposed through the insulative pedestal;electroplating a magnetic material to form a first magnetic pole and asecond magnetic pole overlying the insulative pedestal, the firstmagnetic pole being integrally, physically, and magnetically coupled tothe first side pole and extending from the first side pole toward thesecond side pole, the second magnetic pole being integrally, physically,and magnetically coupled to the second side pole and extending from thesecond side pole toward the first magnetic pole; depositing anon-magnetic material in a gap region separating the first and secondmagnetic poles; forming a diamond-like carbon (DLC) frame extendinglaterally in a plane substantially parallel to the planar surface of thesubstrate and overlying the insulative pedestal, the DLC frame laterallyenclosing the first and second magnetic poles; and planarizing the DLCframe, the first and second magnetic poles, and the gap region to form asubstantially flush upper surface so that the DLC frame suppliesstructural integrity to the head and wear protection for the enclosedmagnetic poles and gap region.
 8. The method according to claim 7further comprising:forming the gap region in substantially an L-shape ina cross-sectional plane substantially perpendicular to the planarsurface of the substrate and intersecting the first and second sidepoles.
 9. The method according to claim 7 further comprising:depositingan adhesion layer situated between the pedestal and the DLC frame. 10.The method according to claim 7 further comprising:forming the DLC frameto a substantially rectangular geometry.
 11. A method of fabricating amagnetic read/write head apparatus comprising:forming a first seed layeron an insulative substrate having a substantially planar surface;depositing a magnetically permeable material on the first seed layer toform a first pole piece, the first pole piece having a generallyparallel orientation with respect to the substantially planar surface ofthe substrate; depositing the magnetically permeable material on a firstend of the first pole piece to form a second pole piece integral withthe first pole piece in a sequence of levels overlying the first polepiece and stacked in a direction perpendicular to the insulativesubstrate surface using the first seed layer as a common seed layer, thesecond pole piece having a generally perpendicular orientation withrespect to the substantially planar surface of the₋₋ substrate andincluding a plurality of stratified integrated layers all havingsubstantially the same size and shape to form a columnar structure andeach layer being directly connected with a preceding layer, the secondpole piece including a top surface, the first seed layer being common toeach layer of the plurality of integrated layers of the second polepiece; depositing the magnetically permeable material on a second end ofthe first pole piece to form a third pole piece integral with the firstpole piece in a sequence of levels overlying the first pole piece andstacked in a direction perpendicular to the insulative substrate surfaceusing the first seed layer as a common seed layer, the third pole piecehaving a generally perpendicular orientation with respect to thesubstantially planar surface of the₋₋ substrate and including aplurality of stratified integrated layers all having substantially thesame size and shape to form a columnar structure and each layer beingdirectly connected with a preceding layer, the third pole pieceincluding a top surface, the first seed layer being common to each layerof the plurality of integrated layers of the third pole piece;depositing an insulative body overlying the substrate and enclosing thesecond and third pole pieces in a plurality of layers of an electricallyinsulative material, the layers of the insulative material being builtup in the insulative body alternately with a build-up of the stratifiedintegrated layers of magnetic material in the second pole piece and thethird pole piece; forming an insulative pedestal situated above theinsulative body; etching a plurality of apertures for extending the topsurfaces of the second and third pole pieces, the insulative pedestalenclosing the top surfaces of the second and third pole piecesperipheral to the apertures; depositing a second seed layer on theinsulative body between the second and third pole pieces, the secondseed layer having first and second portions; depositing a layer of themagnetically permeable material integrally, directly and magneticallycoupled with the second pole piece and disposed on the first portion ofthe second seed layer to form a fourth pole piece; depositing a layer ofthe magnetically permeable material integrally, directly andmagnetically coupled with the third pole piece and disposed on thesecond portion of the second seed layer to form a fifth pole piece;etching a gap region between the fourth and fifth pole pieces, the gapregion having a generally normal orientation with respect to thesubstrate and being fabricated from a non-magnetic material; anddepositing a diamond-like carbon (DLC) frame formed overlying theinsulative pedestal and laterally surrounding the fourth and fifth polepieces and the gap region, the DLC frame, the fourth and fifth polepieces, and the gap region having a substantially flush upper surface sothat the DLC frame supplies structural integrity to the head and wearprotection for the enclosed magnetic poles and gap region.
 12. Themethod according to claim 11 further comprising:forming a first coilstructure encircling the second pole piece, the coil structure includinga plurality of coil layers mutually insulated by the layers of theelectrically insulative material within the insulative body, theindividual coil layers of the plurality of coil layers being stacked sothat the plurality of coil layers form columns in the directionperpendicular to the substrate surface, the columns being mutuallyseparated by the electrically insulative material of the insulativebody, the plurality of coil layers being built up alternately with thebuild-up of layers of the insulative body and layers of the magneticmaterial in the second pole piece and the third pole piece.
 13. Themethod according to claim 12 further comprising:forming a second coilstructure encircling the third pole piece, the coil structure includinga plurality of coil layers mutually insulated by the layers of theelectrically insulative material within the insulative body, theindividual coil layers of the plurality of coil layers being stacked sothat the plurality of coil layers form columns in the directionperpendicular to the substrate surface, the columns being mutuallyseparated by the electrically insulative material of the insulativebody, the plurality of coil layers being built up alternately with thebuild-up of layers of the insulative body and layers of the magneticmaterial in the second pole piece and the third pole piece.
 14. Themethod according to claim 11 further comprising:etching the gap regionin a substantially L-shaped form in a cross-sectional planeperpendicular to the substantially planar surface of the substrate. 15.The method according to claim 11 further comprising:forming an adhesionlayer between the pedestal and the DLC frame.
 16. The method accordingto claim 11 further comprising:depositing the DLC frame in asubstantially rectangular geometry.
 17. The method according to claim 11further comprising:etching the gap region on the second seed layerbetween the first portion and the second portion of the second seedlayer.
 18. The method according to claim 11 further comprising:formingthe DLC frame to a hardness greater than approximately 700 Knoop. 19.The method according to claim 11 further comprising:forming the DLCframe to a hardness in a range from approximately 800 Knoop toapproximately 2000 Knoop.